1. Field of the Invention
The present invention relates to a vehicle including a body frame that is able to lean and two front wheels.
2. Description of the Related Art
A vehicle is known and described in International Publication No. 2012/007819. This vehicle includes a right front wheel and a left front wheel, and a body frame that leans.
The vehicle includes a steering force transmission which controls steering angles of the right front wheel and the left front wheel by turning a handlebar. The steering force transmission includes the handlebar, a steering shaft and a tie rod. Grips are located at both ends of the handlebar. The handlebar is fixed to an upper portion of the steering shaft. The steering shaft is connected to the right front wheel and the left front wheel via the tie rod. The right front wheel and the left front wheel are connected together via the tie rod. When a rider turns the handlebar, the tie rod is displaced via the steering shaft, and the right front wheel and the left front wheel which are connected to the tie rod turn about a right turning axis and a left turning axis, respectively. This movement enables the rider to control the turning angles of the right front wheel and the left front wheel.
In a vehicle with a right front wheel and a left front wheel, since the right front wheel and the left front wheel pass over different road surfaces, a frictional force generated between the right front wheel and the corresponding road surface may differ from a frictional force generated between the left front wheel and the corresponding road surface. Since road surfaces on which the right front wheel and the left front wheel pass change moment by moment while the vehicle is traveling, the frictional forces acting on the right front wheel and the left front wheel also change moment by moment. When a frictional force generated between the right front wheel and the corresponding road surface differs from a frictional force generated between the left front wheel and the corresponding road surface, vibration is generated in a tie rod which is connected to the right front wheel and the left front wheel. This vibration is transmitted to grips via a steering shaft and a handlebar, which may cause a rider discomfort. Since the rider grips the grips when the brakes are applied, the vibration due to different behaviors of the right front wheel and the left front wheel when the brakes are applied tends to be transmitted to the rider.